In recent years, in a color display device which is used for image display of a computer, a television, or the like, a plasma display device which uses a plasma display panel (hereinafter, refers to as a ‘PDP’ or a ‘panel’) has received attention as a color display panel which can realize a thin thickness and a lightness with a large size.
The plasma display device performs full color display by performing an additive color mixture of so-called three primary colors (red, green, blue). In order to perform such a full color display, the plasma display device includes phosphor layers which emit light components of the three primary colors, which are red (R), green (G), and blue (B). A phosphor particle constituting the phosphor layer is excited by ultraviolet rays generated inside discharge cells of the PDP to emit visible light of each color.
As chemical compounds used as color phosphors, for example, (Y, Gd)BO3:Eu, Y2O3:Eu which emits a red light component, Zn2SiO4:Mn which emits a green light component, BaMgAl10O17:Eu which emits a blue light component are known. As a method of manufacturing each of the phosphors, an example in which predetermined raw materials are mixed with each other and then solid-phase reaction is performed by baking the mixture at a temperature of 1000° C. or more is disclosed at ‘phosphor handbook’ (pp. 219-220, published by Ohmsha, Ltd.). Further, the phosphor particle obtained by the baking process is apt to be sintered by the baking process. Therefore, the phosphor particle is used after being grinded and sorted (a mean particle size of red and green phosphor is 2 μm to 5 μm, a mean particle size of blue phosphor is 3 μm to 10 μm.
However, since a phosphor particle of the conventional Zn2SiO4:Mn which emits a green light component is manufactured through a grinding process after solid-phase reaction, stress is applied to a surface of the phosphor particle to occur strain, and various defects such as so-called oxygen defect are generated. Therefore, there is a problem in that such a defect absorbs water contained in the atmosphere during the process of manufacturing the panel, water reacts with the phosphor inside the panel during the time of raising the temperature when the panel is sealed up, such that the brightness of the phosphor deteriorates. Further, the defect absorbs ultraviolet rays of 147 nm which is generated due to the discharge, such that the excitation of the light-emitting center is interrupted. Furthermore, there is another problem in that water reacts with MgO serving as a protecting film inside the panel to cause an address discharge miss. Further, the phosphor of Zn2SiO4:Mn is easily suffered from ion impaction. As a result, there is still another problem in that the deterioration of the brightness is significant, such that sufficiently high brightness can not be obtained. Furthermore, since the Zn2SiO4:Mn is negatively-charged, the charging tendency thereof is different from that of the red phosphor or the blue phosphor. Therefore, there is problem in that the discharge error may be easily generated.